Written by Associated Press on July 8, 2014

WASHINGTON — Europe’s busiest airport — Heathrow in London — is telling passengers that they might not be allowed to take electronic devices onto planes if the device can’t be switched on, to show airport security that it isn’t actually a bomb.

U.S. officials have been concerned about new efforts by al-Qaida to produce a bomb that would go undetected through airport security. According to a counterterrorism official, there’s intelligence indicating that al-Qaida and other groups are trying to perfect an explosive that could be hidden in shoes, electronics or cosmetics.

The Transportation Security Administration isn’t saying just which foreign airports are adopting the requirement that cell phones and other electronic devices be turned on at security.

British Airways has issued an update for passengers flying from Britain to the United States. It says if customers are asked to turn on an electronic or battery-powered device, and they’re not able to do so, they won’t be allowed to fly.